Hectographic duplicating machines



April 18, 1961 F. R. BONSCH HECTOGRAPHIC DUPLICATING MACHINES 4Sheets-Sheet 1 Filed Dec. 19, 1957 Mwavwe April 18, 1961 F. R. BoNscHHECTOGRAPHIC DUPLICATING MACHINES 4 Sheets-Sheet 2 Filed Dec. 19, 1957IllllIIlllllllllllllllllflllll lllllil No 1 Q- April 18, 1961 F. R.BONSCH 2,939,014

HECTOGRAPHIC DUPLICATING MACHINES Filed Dec. 19, 1957 4 Sheets-Sheet 3 Aril 18, 1961 F. R. BONSCH 2,980,014

HECTOGRAPHIC DUPLICATING MACHINES Filed Dec. 19, 1957 4 Sheets-Sheet 4 v45 FIGS. 44

FIG .7.

UIIEEQ 2,980,014 HECTOGRAPHIC DUPLICATING MACHINES rancois RodolpheBonsch, Paris, France, assignor to Block & Anderson Limited, London,England, a British company The present invention relates to hectographicduplicating machines and more particularly to machines of the rotarydrum type adapted to take copies of selected items from the hectographicmaster sheet carried by the. printing drum.

Machines of the type above referred to usually comprise a printingcouple consisting of a rotatable printing drum and a counterpressureroller mounted with its axis parallel to that of the drum, thehectographic master sheet being held wrapped round the surface of theprinting drum and the copy sheets being fed to the nip between theprinting drum and the counterpressure roller after the surface of thecopy sheet which is to contact the master sheet has been moistened by asolvent for the hectographic ink of the master.

A need has already been demonstrated forfletf ecting selectiveduplicating with machines of this type. For example, in productioncontrol systems for use inindustry it is often necessary to prepare anumber of copies each bearing a common heading and a selected one ormore of a number of separate items carried on the mas-v ter sheet inaddition to the aforesaid common heading. The selected item or items maybe at a random positioning among the group of items on the master sheetand the desired form of the resultant copy is that having the commonheading at the top of the sheet followed by each of the selected itemsat regularly spaced intervals. thereunder.

It is a general object of this invention to provide a machine embodyingimproved means whereby selective. copying either of a random selectionor of a consecutive selection of the items of the master sheet may becarried out simply and expeditiously.

According to the broadest aspect of the present invention a hectographicduplicating machine of the type which includes a rotatable printing drumadapted to carry the hectographic master sheet with its lines of textlying parallel with the axis of the drum, is so constructed that theworking peripheral surface of such drum includes an arcuate region whichis sub-divided into a number of separate segments each of which isindividually displaceable in a radial direction relativeto the drum axisbetween the printing position and an inoperative position which isnearer to the drum axis than said printing position.

In a preferred embodiment according to the invention, the normalposition of each of the said separate segments is that of the aforesaidinward or inoperative position, at which position they lie with theirrespective peripheral printing surfaces at a common radial distance fromthe drum axis, and means are provided for individually displacing eachof said separate segments radially outwards to the printing position atwhich the centre of the peripheral printing surface of each displacedsegment lies at a predetermined second radial distance from the drumaxis which is greater than the first radial distance and which is equalto the radius of theundiyided region of the drum surface. By making thecircumferential States Patent:

Patented Apr. 18, 1961 arcuate spacing distance between the centres ofadjacent printing segments equal to the line spacing dimension of themaster copy sheet text, any desired one or any desired selection of theseparate text lines of the master sheet may be selectively copied bydisplacing the related printing segments to the outward or printingposition while leaving the segments related to the unwanted text linesat their inward or inoperative positions.

During each printing operation effected by rotation of the printingdrum, the copy sheet is advanced by its gripping engagement in the nipbetween the printing drum and the counterpressure roller but, owing tothe reduced radial dimension of those segments of the drum which are intheir inoperative position, the copy sheet is not subjected to anyappreciable advancing movement. while such segments are opposite thecounterpressure roller in view of the virtual absence of any grippingpressure thereon so that the copy sheet is effectively advanced only byeach printing segment which is in the printing position and then by adistance corresponding to the arcuate circumferential width of theprinting segment or of the plurality of segments if two or moreconsecutive segments are in use. The copy sheet accordingly re-, mainssubstantially stationary during the periods when the inoperativeprinting segments are passing the counterpressure roller so that theselected text lines are printed at a uniform spacing distance apartbeneath the common heading of the master sheet in spite of the fact thatvarious selected text lines of the master sheet are themselvesirregularly spaced with respect to one. an.- other.

Although the effective displacement of each printing segment isrequired. to be in a radial direction with re.- spect to the drum axis,such movement is conveniently achieved through the, intermediary of acompound mo tion which is partly radial and partly axial in directionand according to a further feature of the invention manually operablecontrol means are provided for placing each individual printing segmentor any number of printing segments into the printing position by meansof such compound movement.

The invention further comprises control means, which may be eithermanually or automatically operated, for moving in turn, duringsuccessive revolutions of the printing drum, each printing segment orany desired combination of consecutive printing segments into theprinting position to elfect the copying of single text line items orgroups, of text line items in sequence upon successive copy sheetsapplied to the machine. The manually operable control means may furtherinclude or be combined with means for locking any selected printingsegment or combination of printing segments in the printing position soas to facilitate repeat" copying from such combination.

In order that the nature of the invention may be more readily understooda practical embodiment thereof will now be described in greater detailbut by Way of illustrative example only with reference to theaccompanying drawings in which:

Figure 1 is a sectional side elevational view of a typical known formof'rotary duplicating machine having the present invention embodiedtherein.

Figure 2 is a longitudinal section through the axis of thelprinting drumshown in Fig. l, drawn to an enlarged sca c.

Figure 3 is a transverse cross-section taken on the line HI-III of Fig.2.

Figure 4 is a transverse cross-section taken on the line IV--IV of Fig.2.

Figure 5 is a further-fragmentary cross-section on the line V-V of'Fig.2.

3 Figure 6 is a diagrammatic view illustrating the manner of operation.

Figure 7 is a fragmentary detail view. 7 The inventionwill be describedas applied to a simple hand-driven duplicating machine and as shown inFig. 1 this comprises a cylindrical printing drum 10 mounted forrotation about the substantially horizontal and stationary axle 11secured between opposed vertical side plates 12 forming part of thestationary framework of the machine. The drum 10 is rotated, onerevolution for each machine operation, by means of a hand-operated crankarm 13 through meshing gear wheels 14 and 15, the gear wheel 15 beingrigidly connected to the printing drum and the gear wheel 14 beingcoupled to the crank arm 13 and journalled in one of the side plates 12.

The printing drum co-operates/with a counter-pressure roller 16 which isjournalled for rotation between the side plates 12 about an axisparallel with that of the drum 10 at a position, in the example shown,almost vertically beneath the drum axle 11. This counterpressure roller16 forms a printing couple in conjunction with the printing drum 10 andis provided with means for varying the printing pressure exerted betweenit and the drum. As shown, such means comprises a horizontal shaft 17journalled in the side plates 12 and provided with a pair of rigidlyconnected spaced arms 18 having 'the counterpressure roller 16journalled in their free ends. A lever arm 19 also rigidly connected tothe shaft 17 is provided at its outer end with means 20 for securing itin any one of a number of angular settings relative to the machineframework.

The master sheet, indicated at M, is secured to the printing drum 10 bygripping its upper edge within the clip shown at 21 and comprising, inknown manner, a radially movable bar having a chamfered clamping edgeand slidable within a correspondingly shaped radial slot in the printingdrum. Such clip 21 is operated by mechanism, not shown, of any suitableknown form so as to be capable of being opened when the drum 10 is inthe position as indicated to receive the edge of the master sheet Minserted in the channel formed between the outer acetic After passingthrough the printing couple the copy sheet is delivered to the deliverytray 28.

Whereas'in the machines of the prior art, the drum 10 is normallyarranged to have a smooth cylindrical peripheral working surface ofconstant radius and un broken except for the master clamping clip 21, inthe machine according to the invention an arcuate region of suchsurface, for example, approximately 180, is subdivided into a number ofseparate printing segments 30 each of which is arranged to beindividually displaceable in a radial direction with respect to the drumaxis between an inner position, where the radial distance between theperipheral printing surface thereof and the drum axis is less than theradius of the remaining undivided region 31 of the drum surface, and anouter or printing position where such radial distance is equal to theradius of the undivided region 31. Means, as described later, areprovided for controlling the position of each printing segment surfaceof the drum and an arcuate guide plate 22 secured between the sideplates 12. Closure of the clip 21 secures such forward edge in knownmanner whereby the master sheet becomes wrapped around the printing drum1t! upon its rotation.

Copy sheets are received upon the feed plate 23 also secured between theside plates 12, the forward edge of the copy sheet entering the bightbetween opposed sheet feeding and moistening rollers 24, 25 respectivelywhich are also journalled in the side plates 12.

These rollers 24, 25 are arranged to be driven intermittently in wellknown manner from the printing drum crank arm 13, e.g. through anoscillating gear sector and a unidirectional drive device, whereby theyare positively rotated for a brief period at the commencement of and intimed relationship to each revolution of the drum 10. By such rotationeach applied copy sheet is fed forwardly over the support plate 26 tothe operative nip between the printing drum 10 and the counterpressureroller 16. The duration and timing of the positive drive imparted to therollers 24, 25 is such as to advance the copy sheet from the initiallaying-on position to that atwhich the forward edge of the copy sheet isgripped by the printing couple just after the clip 21 has passed thecounterpressure roller 16. Thereafter further forward movement of thecopy sheet is effected only by the grip exerted thereon in the nip ofthe printing couple. Moistening of the copy sheet is eifected, in theexample shown, by moistening fluid applied through a pad 27 resting uponthe upper surface region of the roller 25 whereby it becomes transferredto the upper surface of the copy sheet immediately prior to the entry ofthe sheet into the nip of the printing couple where such moistenedsurface comes in contact with the image-bearing surface of the mastersheet M.

whereby it may be placed in one or other of the two positions for thewhole of one or more revolutions of the drum.

The manner of operation of the machine with such an arrangement ofseparate printing segments is best explained with reference to thediagram of Fig. 6. The

master sheet M, held by its upper (sheet) edge on the,

clip 21 is provided with a plurality of separate lines of text m1, m2,m3 mlii, m11 disposed to lie parallel with the drum axis. The spacingbetween each of these lines is arranged to be equal to the arcuatespacing distance between the centres of adjacent printing segments whilethe text lines themselves are arranged to register one with eachsegment. It will be assumed that, as shown, the printing segmentsnumbered 2, 5 and 9 have been moved to the outward, printing positionwhereas the remaining segments are at the inward, inoperative position.

The copy sheet C, fed forwardly by the rollers 24 and 25 enters the nipbetween drum 1t and counterpressure roller 16 just behind the clip 21 sothat the master sheet M and the copy sheet C are fed forwardly in unisonuntil the printing segment 1 comes opposite the counterpressure roller16. Owing to the inward positioning of such printing segment, there isnow no pressure by the roller 16 upon the drum 10 and in consequence theforward movement of the copy sheet is arrested and printing of the textline 1111 is not effected. Upon arrival of the next and operativeprinting segment 2, however, pressure by the roller 16 again takes placewith resultant printing of text line m2 accompanied by forward moverncntof the copy sheet C by an amount determined by the arcuate width of thesegment. In similar manner, printing of text lines m3 and m4 is omittedand no further'forward movement of the copy sheet C occurs until thearrival of printing segment 5 which, being in printing position, printsthe text line m5 immediately beneath the, previously printed text linem2 on the copy sheet C while simultaneously moving the latter forward bythe amount of one line space. Further printing does not occur until thearrival of printing segment 9 which causes printing of text line m9immediately beneath the previously printed line m5. Assuming no furtherprinting segments are in operative position, the final delivery movementof the copy sheet C is effected when the remainder of the undividedregion 31 of the drum it comes opposite the counterpressure roller 16towards the end of the operative revolution of the drum. The form ofthedrum and of the various means associated therewith for controlling theposition of the printing segments will now be described in greaterdetail with reference to Figs. 2-5 and 7.

The drum 10 comprises opposite end plates 32, 33 which are each securedto an arcuate or part-cylindrical member 34, the outer peripheralsurface 35 of which constitutesthe-undivided region 31 of the workingsurface of the drum. This member 34 conveniently extends a un app o im y89 of h rum sirq n sren t To the inner surface of the end plate 32 is"secured a bushing 36 having an outwardly directed integral sleeve 31'adapted to form a bearing for one end of'the drum upon the stationaryaxle 11. "'Secured to inwardly directed ribs 38 of the member 34, atspaced-apart positions disposed inwardly "of the drum, are further webplates 39' provided with central bearing bushings 40 also rotatable uponthe stationary axle 1 1.These web'plates 3.2, over their peripheralregiqnj not covered by the member 34, are radially slotted asshown at41, more particularly in Fig. 3, the respec: tive' slots of the two webplates being in'axial alignment. Mgunted in each pair of aligned slots41 is the web. 42 of a printing segment 3!), such web beingsubstantially thinner than'the'arcuate width of the head portion 43whose curved outer surface 4,4 constitutes the working surfaee of thesegment. Such printing segments are accordingly displaceable within theradial slots 41 in both an axial directionand in a radial direction. Tenv springs 55 extending between the inner edge of the weh 42 of eachsegment and securing means, such as a projecting pin 4.45 on theassociated web plate 3.9, serve to retaineach printing segment inposition.

' The opposite end plate 33 is provided with a number of spring plungers47, one in alignment with each of t W Qf P n i se m nt .0- Su p m seachoperate to, urge the associated printing segment in the direction ofthe arrow 4, As shown more clearly in the detail Fig. 7, the inwardlydirected edge of the web 42 of each printing segment provided with apair of spaced notches 48 positioned to bo operate with the web plates39. One side of each notch of chamfered or ramped form indicated at 49and these ramped regions co-operate respectively with the chamferededge50 of two discs 1 secured one tq eachof the two. web plates 39 whereby,if any printing segment is urged in an axial direction opposite to thatof the arrow a the ramped surfaces 49 ride up the chamfe red edge 50, ofthe discs 51 and thereby, by a compound axial and radial movement of theprinting segment, effect a radial displacement of such segment whichbrings the peripheral working surface 44, theregf to "the outr o roperative position where the radial dis tance between said workingsurface 44 and the axis of the drum is equal to the radial dimension ofthe working nitrate ofthe member 34. I For the purpose of selectivelymoving any printing segment 30 there are provided a plurality ofoperating fingers 53,"one for cash segment 30, at .the end of vthe druinopposite tothe plungers 47. These fingers 53 are each located within anindividual radial slot in the bush ing 36 and have rounded nose ends 54which form ful; eriim'points "therefor and which are located in a se ic'ircular' section channel 55 formed on one radial faee of a furthercollar 56 which is rigidly secured to the inner surface of; the endbushing 36. The opposite, outer end of each 'finger5 3 is provided witha projection 53;; adapted to engage the end of the associated web. 42;.Disposed to'ro'ta'te around the sleeve 37 of the bushing 36 on theoutside of the end plate 32 are a number of separate setting or controllevers 57 each of which is prdvidedwith an axially directed projection53 adapted to pass'throug'h an arcuate slot 5.9 in the end plate and',"according to the setting position of the le er, to engage and rolcle achosen. one of the fingers 53; about, its'"'fulcrum end 54.

hen that n ages and rocked e. e ected 53 applies the required axialforce to the assoeiated printing ment 3!! 9" an; ncreme thereof rom, itn rm indperative'p osition to its operative or printing position. Theamount of. axial movement is preferably such that the axially directededge surface of the. web. 42 rests upon similar axially directedsurfaces at the bottom Otthg $19 2 er ele en ny axiall d s d 6 reac to-e ,19 .1 he se ment whe prin in pre ure s pplied th',. etc. by the co ne p ure r ler 1n.

The two in'n'er control levers 57 are shown arranged for purely manualsetting prior to each operation of the machine but the third andoutermost lever 57 is shown also adapted for automatic alteration by onestep at the end of each operative revolution of theprinting drum. Suchmeans comprise the formation of the hub of the lever with an enlargedratchet-toothed sector 6t)v around its outer edge. These ratchet teethare engaged by a pawl 61 carried upon a rocking lever arm 62 pivotallymounted on the end plate 32 and co-operating with a locking pin 6 3..The lever arm 62 is spring-urged, by means not shown, to the positionindicated in Fig. 4 while the outer end of the interconnected arm 64 isadapted to come. into engagement, at the end of each revolution of thedrum 1 0,'with a stationary abutment 65 carried on the. adjacent sideplate 12 whereby the lever arm 6,2 is rocked to shift the sector 60 bythe amount of one. tooth. This movement alters the setting position ofthe associated control lever 57 by the amount of the angular spacingbetween adjacent operating fingers 53,

By means of the above-described arrangement of operating fingers 53 andcontrol levers 57 any chosen two text lines ofthe master can bepre-selected as a constant heading and each of the further text linesautomatically selected for operative use in'turn during successiverevolutions of the printing drum. If a facility for using a greaternumber of heading lines is desired the number of manually set controllevers may obviously be in: creased while, if desired, the angularextent of the projections 58 carried by one or more of the controllevers 57 can be increased to rock two or more of the operating fingers53 simultaneously. The abutment 65 is, con-l veniently mounted upon aroeker arm connected to a manual control member whereby it can be movedout of the path of the arm 64 when automatic. change of they ope t Pntin e me is n t equ r d.

At e QPPQSi s and .t e r m. there are illu trated. alternative means forcontrolling the selection and dis: placement of the printing segmentsinto operative position. These means comprise the formation ofadditional notches 66., 6'7 in each of the webs 42. Th nOtch 6 6'co-operates with a first rotatable disc 7!} fixed to. the inner end of atubular bushing 71 rotatable on the fixed axle 11 The opposite end ofthis bushing, on the outer side of the end plate 33 has secured theretoa control lever 72 which may resemble the levers 57. Over a pre;determined arc the peripheral region of the disc 70 is provided witheither a contoured rail or, as shown, an integral offset region 73adapted to form a ramp or cam surface of effective length embracing achosen number, say. two, of the webs 42 of the printing segments 30.Such ramp region 73 acts upon the radialedge surface of the notches 66with which it is in registerto displace the associated printing segments30 in an axial direction and thereby to produce an accompanying radialoutward movement by reason of the ramp surfaces. 49 and chamfered edges50 of the discs 51. By appropriate angular setting of the control lever72 any desired two adjacent printing segments may be displaced to theoperative posi-. tion. A second generally similar disc 74, connected byway of bushing 75 to, a control lever 76, has a ramp. region 77extending over only one web. 42; This disc co-operates. with the notch67 and provides for-movement of the printing segments singly. It will beunder: stood that the ramp 'regions such as 73 and '77 may be of anydesired arcuate length so as simultaneously to control any desirednumber of printing segments. It is also possible to employ a disc havinga ramp surface extending over the entire arcuate length occupied byprinting "segments, e g. in the example shown. By appropriate,positioning. of such a disc either the first or s ta l a t??? 33; e. itlsssd qr. anrdesimtl mama consecutive number of printing segmentsincluding such first or last segment. If desired the control levers 72,76 may be provided with means similar to the toothed sector 60 on lever57 and its associated parts, for effecting automatic progression of theoperative printing segments during successive revolutions of theprinting drum.

Various modifications may clearly be made without departing from thescope of the invention. For example, although the invention has beendescribed in connection with a manually operated machine, it is clearlyequally applicable to a power driven machine. The separate printingelements into which a part of the drum is subdivided have been referredto as segments but it is to be understood that this term does notrestrict the cross-sectional form to that shown. Other cross-sectionsmay obviously be used. The various control levers, such as shown at 57,may be arranged to operate directly upon the printing segments insteadof through the intermediary of operating fingers while in anotherpossible modification each segment has an individual setting controlmember associated therewith in the form of an aligned and radiallymovable press button. Although in the example described the arcuatewidth of each segment is arranged to be equal to the line spacingdistance of the master sheet it is possible to employ the other widths,for instance, equal to an integral multiple or a vulgar fraction of theline spacing distance.

I claim:

1. A hectographic duplicating machine including a printing andcopy-sheet feeding couple comprising a ro tatable printing drum and acounterpressure roller mounted for rotation on an axis parallel to butspaced from the axis of said drum, said drum including means forsecuring an image-bearing member thereto and wrapped at least partiallytherearound with its respective lines of image text directed parallel tothe axis of said drum, a plurality of similar printing segments disposedparallel with said drum axis and forming that part of the peripheralsurface of said drum which underlies the image-bearing portion of saidimage-bearing member, said segments each having a circumferential widthequal to and positioned to underlie and support one text line area ofsaid image-bearing member, means for supporting each segment in a firstposition in which said segments conjointly form a part-cylindricalsupporting surface for said image-bearing member and of a radius lessthan that necessary to provide printing and copy-sheet feeding pressureat the printing bight between said drum and said counterpressure rollerand means for effecting individual displacement of any chosen one ofsaid segments in a radially outward direction to a second position wherethe peripheral surface thereof provides a part-cylindrical surfacehaving a radius from the drum axis sufiicient to effect both printingand copy-sheet feeding movement in conjunction with said counterpressureroller at the printing bight of said printing couple.

2. A hectographic duplicating machine according to claim 1 whichincludes means for displacing a chosen printing segment or combinationof segments prior to commencement of an operative revolution of theprint ing drum and for retaining such displacement until at least theend of said operative revolution of the drum.

3. A hectographic duplicating machine including a printing andcopy-sheet feeding couple comprising a rotatable printing drum and arotatable counterpressure roller mounted for rotation on an axisparallel to the axis of said drum, said drum including means forsecuring an image-bearing master sheet therearound with its respectivelines of image text directed parallel to the axis of said drum, thatpart of said drum which underlies the image-text region of said mastersheet being constituted by a plurality of separate printing segments ofequal circumferential width disposed side-by-side and parallel with saiddrum axis with each segment positioned to underlie a different one ofsaid image-text lines 8 T of said master sheet, said segments normallyforming a part-cylindrical surface for supporting the image region ofsaid master sheet at a radius from said drum axis which will not produceeither printing of the master image or forward feeding movement of thecopy-sheet at the printing bight of said printing couple, and means foreifecting individual'displacement of any chosen plurality of saidsegments 'in a radial direction to an outward printing position wherethe peripheral surfaces thereof are each at a radius from the axis ofsaid drum appropriate to provide both printing pressure and copy-sheetfeeding movement at said printing bight of said printing couple.

4. A hectographic duplicating machine including a printing andcopy-sheet feeding couple comprising a rotatable printing drum and arotatable counterpressure roller mounted for rotation on an axisparallel to the axis of said drum, said drum including means forsecuring an image-bearing master sheet therearound with its respectivelines of image text directed parallel to the axis of said drum, thatpart of said drum which underlies the image-text region of said mastersheet being constituted by a plurality of separate printing segments ofequal circumferential width disposed side-by-side and parallel with saiddrum axis with each segment positioned to underlie a different one ofsaid image-text lines of said master sheet, said segments normallyforming a partcylindrical surface for supporting the image region ofsaid master sheet at a radius from said drum axis which will not produceeither printing of the master also or forward feeding movement of thecopy-sheet at the printing bight of said printing couple, and means foreffecting during successive revolutions of said drum, the individualdisplacement of each of said segments in turn in a radial direction toan outward printing position where the peripheral surface thereof is ata radius from the axis of said drum appropriate to provide both printingpressure and copy-sheet feeding movement at said printing bight of saidprinting couple.

5. A hectographic duplicating machine according to claim 1 in which saidsegment displacement means include individual motion translating meansfor each segment by which said radial displacement movement is obtainedby a compound motion of such segment in both a radial and an axialdirection.

6. A hectographic duplicating machine according to claim 5 whichincludes segment setting means operable to applyan axially directedforce to a segment chosen for displacement in a radially outwarddirection.

7. A hectographic duplicating machine according to claim 6 whichincludes means slidably mounting each of said segments in said printingdrum for movement in a direction parallel with the drum axis, saidslidable mounting means including axially spaced inclined surfaces oneach segment and co-operating axially spaced inclined surfaces on saiddrum.

8. A hectographic duplicating machine according to claim 7 whichincludes at least one displaceable control member carrying an abutmentselectively registrable with at least one of said printing segments toapply said axially directed displacement force thereto.

9. A hectographic duplicating machine according to claim 7 whichincludes a rotatable setting member within said printing drum, saidrotatable setting member having a peripheral oflfset region arranged forengagement with a co-operating abutment surface on each of said segmentsto apply said axially directed displacement force thereto.

10. A hectographic duplicating machine according to claim 8 in whichsaid control member is arranged to operate upon said segment or group ofsegments through the intermediary of pivotal operating fingers.

11. A hectographic duplicating machine including a printing andcopy-sheet feeding couple comprising a rotatable printing drum and arotatable counterpressure roller mounted for rotation on an axisparallel to the 9 axis of said drum, said drum including means forsecuring an image-bearing master sheet therearound with its respectivelines of image text directed parallel to the axis of said drum, thatpart of said drum which underlies the image-text region of said mastersheet being constituted by a plurality of separate printing segments ofequal circumferential width disposed side-by-side and parallel with saiddrum axis with each segment positioned to underlie a different one ofsaid image-text lines of said master sheet, said segments normallyforming a part-cylindrical surface for supporting the image region ofsaid master sheet at a radius from said drum axis which will not produceeither printing of the master image or forward feeding movement of thecopy-sheet at the printing bight of said printing couple, and means foreffecting during successive revolutions of said drum,

the individual displacement of different successive groups of saidsegments in a radial direction to an outward printing position where theperipheral surfaces thereof are each at a radius from the axis of saiddrum appropriate to provide both printing pressure and copy-sheetfeeding movement at said printing bight of said printing couple.

12. For a hectographic duplicating or like printing machine, a rotatableprinting drum which includes a first solid part-cylindrical peripheralwall part having a constant radius from the drum axis and a secondpartcylindrical peripheral wall part extending between opposite ends ofsaid first wall part and comprising-a plurality of separate axiallydirected printing segments of equal circumferential width, sheetclamping means in said first wall part for retaining the forward edge ofan image-bearing master sheet to be disposed around and supported bysaid second wall part of said printing drum,

a radially disposed web portion extending inwardly from each of saidseparate printing segments, axially spaced radially slotted guide platesrotatable with said printing drum for supporting said web portions ofsaid printing segments in a manner permitting both axial and radialdisplacement thereof, ramped surfaces on each of said web portions ataxially spaced positions thereof,- correspondingly ramped surfacesfacing each of said ramped web surfaces and carried by and rotatablewith said printing drum, spring means associated with each of saidprinting segments for urging said printing segments inwardly to aposition where their respective peripheral outer surfaces are at aradius from the axis of said drum less than that of said first wallpart, and means for effecting axial displacement of any chosen one ofsaid printing segments to bring said ramped web surfaces into engagementwith said opposing ramped surfaces thereby to move the associated webportion and its attached printing segment radially outwards to aposition where the outwardly facing peripheral surface of said printingsegment lies at a radius from the drum axisequal'to said first wallpart. v

13. For a hectographic duplicating or like printing machine, a rotatableprinting drum which includes afirst solid part-cylindrical peripheralWall 'part having a constant radius from the drum axis and a secondpartcylindrical peripheral wall part extending between opposite ends ofsaid first wall part and comprising a plurality of separate axiallydirected printing segments of equal circumferential width, sheetclamping means in said first wall part for retaining the forward edge ofan image-bearing master sheet to be disposed around and supported bysaid second wall part of said printing drum,

a radially disposed inwardly directed web portion extending inwardlyfrom each of said separate printing segments, axially spaced radiallyslotted guide plates rotatable with said printing drum for supportingsaid web portions of said printing segments in a manner permitting bothaxial and radial displacement thereof, a plurality of notches eachhaving a ramped surface at one end in each of said web portions ataxially spaced positions therein, a plurality of members havingcorrespondingly ramped surfaces facing each of said ramped web surfaces,said members being carried by and, rotatable with said printing drum,spring means associated With each of said printing segments for urgingsaid printing segments inwardly to a position where their respectiveperipheral outer surfaces are at a radius from the axis of said drumless than that of said first wall part, and means for effecting axialdisplacement of any chosen one of said printing segments to bring saidramped web surfaces into engagement with said opposing ramped surfacesthereby to move the associated web portion and its attached printingsegment radially outwards to a position where the outwardly facingperipheral surface of said printing segment lies at a radius from thedrum axis equal to said first wall part.

14. Fora hectographic duplicating or like printing machine, a rotatableprinting drum which includes a first solid part-cylindrical peripheralwall part having a constant radius from the drum axis and a secondpartcylindrical peripheral wall part extending between opposite ends ofsaid first wall part and comprising a plurality of separate axiallydirected printing segments of equal circumferential width, sheetclamping means in said first wall part for retaining the forward edge ofan image-bearing master sheet to be disposed around and supported bysaid second wall part of said printing drum, a radially disposed webportion extending inwardly from each of said separate printing segments,axially spaced radially slotted guide plates rotatable with saidprinting drum for supporting said web portions of said printing segmentsin a manner permitting both axial and radial displacement thereof,ramped surfaces on each of said web portions at axially spaced positionsthereof, correspondingly ramped surfaces facing each of said ramped websurfaces and carried by and rotatable with said printing drum, springmeans associated with each of said printing segments for urging saidprinting segments inwardly to a position where their respectiveperipheral outer surfaces are at a radius from the axis of said drumless than that of said first wall part, and means for effecting axialdisplacement of any chosen plurality of said printing segments to bringsaid ramped Web surfaces thereof into engagement .with said opposingramped surfaces thereby to move each of the associated web portions andtheir attached printing segments radially outwards to .positions wherethe outwardly facing peripheral surface of each of said printingsegments lies at a radius frornthe drum axis equal to said first wallpart.

References Cited in the file of this patent 2,421,823 Allen et a1. June10,

